Toggle press



9, I H. c, BOSTWICK 2,310,674

TOGGLE PRESS Filed May 28, 1957 Sheets-Sheet 1' a I INVENTOR! HENRY CB057'W/CK ATTORNEY$ Feb 9, 1943. v wjc 2,310,674

- QYTOGGLE PRESS Filed May 28, 1937 4 Sheets-Sheet 4 1N VENT OR. HENIFYC BOJTW/CK ATTORNEYS Patented Feb. 9, 1943 TO GGLE PRESS Henry C.Bostwick, Akron, Ohio, assignor to Akron Standard Mold Company, Akron,Ohio, a

corporation of Ohio Application May 28, 1937, Serial No. 145,241

8 Claims.

This invention relates to molding and vulcanizing presses andparticularly to those wherein the mating mold sections are relativelymovable, and wherein one of the sections is tiltable with reference tothe other so as to facilitate the insertion and withdrawal of anarticle.

The invention is shown in connection with a toggle operated press andhas for one of its objects the provision of a motor drive wherein themotor is supported independently of the toggles so as to providesuflicient clearance between the mold sections to permit adequatetilting of the lower section for facilitating insertion and withdrawalof an article.

An additional object is to provide a press wherein the toggle mechanismmay be utilized for bringing the mold sections into engagement with eachother but where the article forming pressure is exerted by a fluidoperated device that operates independently of the toggle mechanism.

A further object is to make a toggle operated press wherein the pressurebetween the mold sections is obtained entirely by movement of the togglemechanism, but wherein the position of the stationary mold section maybe readily varied or adjusted to insure a uniform contact between allparts of the mold sections at the completion of the closing operation,

Referring now to the drawings, Fig. 1 is a front view of a press whichembodies one form of my invention; Fig. 2 is a section taken on theplane indicated by the lines 22 in Fig. 1, the closed position of thepress being indicated by the full lines and the open position by brokenlines; Fig. 3 is a detailed section on an enlarged scale showing themechanism for operating one of the mold sections independently of thetoggle mechanism; Fig. 4 is a section taken on a plane indicated by theline 4-4 in Fig. 3, and Fig. 5 is a section taken on a large scale on aplane indicated by the lines 5-5 in Fig. 4; Fig. 6 is a front viewpartly in section of a press which embodies the modification of myinvention, that part of the press which is illustrated in section beingtaken on a plane indicated by the line 6-6 in Fig. 7; Fig. 'l is asection taken on the plane indicated by the line 1--'! in Fig. 6; andFig. 9 is a section taken on a plane indicated by the line 9--9 in Fig,2.

Referring now to Figs. 1 to 5 inclusive, I0 represents a base to whichare attached the lower ends of a pair of upwardly and rearwardlyinclined side frame plates II. A press head carrier 12 is attached tothe upper ends of the side plates and is arranged to support an upperpress head ,sent the molded article in a more favorable position forinsertion or withdrawal with respect to the mold.

The mechanism for reciprocatin and tilting the lower mold sectionpreferably comprises toggle units that are formed by double pairs oflinks l8, I9, 20, and 2!, which are pivotally connected to the lowersection and to the base respectively at 22, 23, 24 and 25. The pair oflinks 18 and [S .are interconnected by a pivot 26, while each pair oflinks 20 and 2| is interconnected by a pivot 21. In the closed positionof the press, the links occupy the full line position, as shown in Fig.2, while in the open condition the links occupy the position shown bybroken lines l8a, I9a, 20-11, and 2 l-a respectively. Similarly theposition of the lower head and carrier in the closed condition of thepress is shown in full lines in Fig. 2; while the open condition isshown by the broken lines I6--a and I'la.

The mechanism for actuating the toggles comprises a screw and nut couplein the form of a threaded spindle 28 and a. coacting threaded sleeve 29.The spindle projects beyond one end of the sleeve and is connected tothe toggle pivot 26, as by a swivel block 30 and a pin 3|. The screw andnut couple forms an extensible device that is enclosed within a. housing32, which in turn is journaled in the frame at 33 on trunnions 34. Thehousing supports an electric motor 35 and encases reduction gears 36 and31 which provide an operative connection between the motor shaft 38 andthe sleeve 29. The motor is reversible and is provided with suitablelimit switches,

.which are adapted automatically to disconnect the source of currentsupply to the motor, as the movable mold section approaches its upperand lower limits of travel.

In the press construction illustrated in Figs. 1

and 2, the toggles are utilized for moving the lower mold section intoclose fitting but not into pressing engagement with the upper section.The pressiig engagement is effected by a fluid actu- 13, which carries amold section M. ,The head ated mechanism, which forces the upper sectionagainst the lower section after the pairs of toggle links have reached astraight line position.

One form of mechanism for applying pressure to the upper sectionembodies a diaphragm 40 which extends between the carrier i2 and theupper head 13 and which is fixed to the carrier at its outer peripheryas by an annular clamping plate ii, and which is fixed at its innerperiphery to the plate 45 which in turn rests upon the upper surface ofthe head [3, as by securing members 59. The plate 45 is shown as havinga central aperture 41 into which a sleeve 48 extends, and the sleeve inturn carries the flange through which the diaphragm securing bolts 49may be passed. The internal portion of the sleeve may be threaded toreceive a plug 53 so that the plug, sleeve, and diaphragm coact toprovide the bottom wall of a chamber the top wall of which is formed bythe under side of the carrier l2. Air under pressure may be supplied tosuch chamber through a conduit 52 (as shown in Fig. 3).

The diaphragm comprises a wall of a fluid tight compartment which may beutilized as an expansion chamber for exerting a continuous yieldablepressure against the mold sections after the toggle links have beenstraightened during the closing movement of the press. Accordingly, thepressing units are so arranged with respect to each other that the lowerunit lifts the upper mold section and head as a unit, until the head islifted off the seats which comprise nuts 55 on bolts 55. The extent ofmovement of the head off the seats 55 is sufiicient to allow a slightreturn movement under the action of the diaphragm it; this returnmovement being utilizable to perform the final step in the pressureexerting process.

The bolts 55 extend through passageways 51 adjacent the corners of thecarrier member I2. Intermediate the corner bolts, I have shown suitableguide pins 53 which may be carried by the head l3, and may extendthrough suitable apertures 59 in the carrier l2. The bolts 55,therefore, support the upper mold section, and yet allow a slightreciprocation thereof after the lower mold section has been elevated tothe ex treme limit of its upward travel.

To release the pressure within the chamber 5! at the completion of apressing operation, I utilize a valve 69 which is carried on a stem 6%,and which is adapted to bear against a seat 52, under the action of aspring 63. The fluid pressure within the chamber also acts to retain thevalve 60 against its seat. The valve however, is adapted to be opened bya predetermined movement of the plate 45, the opening occurring by theengagement of a part that is carried by the plate with a stop on thestem 6!. The part referred to is illustrated, as a washer 64, which isheld in place within the sleeve 48 by the plug 513. The stop referred toon the stem may comprise a nut 65 which is adjustably positioned on thestem, and which is adapted to occupy a pocket 55 in the plug; thus,whenever the valve 60 is unseated, the fluid within the chamber 5| isallowed to escape to the atmosphere through the passageways G1 and 63.

To permit slight reciprocation of the upper mold section with referenceto the carrier [2, the plate 45 has a peripheral flange 59, whichoverlies an inwardly extending flange on the ring 4| as shown in Fig. 3.Prior to the assembly of the upper mold section to the carrier, theflange 69 rests on the flange 10 and thereby supports the plate 45 withrespect to the carrier I2,

but the relationship is such that when the head l3 rests upon the seats55, there is a slight clearance between the flanges 69 and 10, at whichtime the weight of the plate is supported by the bolts 55. However, asthe upper section is moved under the influence of the movement of thelower section, the clearance between the flanges 69 and 10 is increasedby an amount, which is equal to the extent to which the upper section islifted oil the seats 55. This amount can be adjusted to permit thedesired return movement of the upper section under the influence of thediaphragm 40.

To interconnect the toggle link pivots 26 and 21 so as to synchronizethe movement therebetween, while obtaining a predetermined relationshipbetween the mold sections at the time of separation, I have shown a pairof links H, each of which is pivotally connected to the pivot 26, andeach of-which is provided with a cam slot 12, in which one of the pivotpins 21 extends. The rearward end of each link H is then connected tothe pivot 25 by a link 13, as shown in Figs. 1 and 2. The function ofthe cam slot 12 is to maintain the proper relationship between thepivots 26 and 21, while the rollers 14 on the pivot pins 24 move alongthe cam slots i 5 in the side plates II; the relationship being such,that whenever the press is open the lower section tilts gradually, as itmoves away from the upper section until clearance is obtained, then ittilts abruptly forwardly, so as to facilitate removal of the articletherefrom. As shown in Fig. 2 the upper portion of the slot 15 isinclined to the axis of the molds, and as a result, the first movementof the tilting action helps to break the connection between the tire andthe mold.

To eject an article that is held within the lower mold section, I haveshown an ejector ring 16 which rests upon the head I5, and which isprovided with a stem 11 that is slidably positioned in apertures withinthe carrier IT. The lower end of the stem projects beyond the bottom ofthe carrier and may be provided with a roller 18 that is adapted toengage a block 19, during the opening operation of the press. The blockmay extend across and be attached to the links 20 at such height that itis engaged by the roller 18, during the forwardly abrupt tiltingmovement of the roller section, as a result of which, the stem projectssufiiciently far beyond the carrier I! so that the ejector ring 16 islifted off the head and the molded article is ejected from the moldsection.

The operation of the press when made according to Figs. 1 and 2 is asfollows: Assuming that the press is in open position, as is shown by thebroken lines in Fig. 2, then the article to be molded is placed upon theejector ring and within the lower mold section, and thereupon current issupplied to the motor so as to rotate it in a direction to elevate thelower mold section. During the elevating movement, the first motion ofthe lower mold section is a tilting one, and this motion continues untilthe rollers 14 arrive at the vertical reach of the cam slots 15, atwhich time the upper surface of the lower mold section is nearlyparallel with the bottom surface of the upper mold section, whereuponcontinued operation of the motor elevates the lower section until thetoggles are straightened.

So long as the lower section remains out of contact with the uppersection, the upper section is supported on the abutments 55 during whichvalve 66 off its seat.

time the washer 64 is in engagement with the stop 65' on the safetyvalve and is holding the As soon as the lower section has lifted theupper section off the seats 55, however, the valve 69 will be closedautomatically under the action of the spring 63, because the extent ofmovement of the lower section with respect to the carrier [2 has raisedthe washer 64 out of contact with the stop 65. When the mold is thusclosed, air under pressure is admitted into the chamber 5| through theconduit 52, and thereupon pressure is exerted against the diaphragm 55,to the plate 45, through the head i3, and thence to the upper moldsection until the vulcanizing operation is completed. It is to beunderstood that steam is to be admitted to the chambers in the heads I?and I8 during the vulcanizing operation.

At the completion of the vulcanizing operation,

the source of air supply to the chamber 5| is cut seat 55, and duringsuch movement, the washer;

64 engages the abutment 65, and thereby opens the valve 65 to exhaustthe air in the chamber 5 I.

' In the meantime, the lower section continues its downward vertical andtilting movement until it eventually reaches the position shown by thebroken lines in Fig. 2. During the latter part of its movement theroller 18 on the ejector pin '71 engages the block 19, and therebyraises the molded article off the lower mold section. At the completionof the movement, the current supply to the motor is disconnected in anysuitable way.

In Figs. 6 and '7, I have shown a modified form of press construction,wherein the fluid pressure actuated diaphragm is eliminated, but whereinan adjustment is provided between the upper head andits carrier, so asto obtain automatically the desired degree of pressure between the upperand lower sections at the time the toggles approximate a straight lineposition, during the closing movement of the press. In Figs. 6 and 7,the entire press construction is not illustrated, it being understoodthat the mechanism for moving the lower section is the same as thatheretofore described. It is also to be understood that the partsillustrated in Figs. 6 and? which correspond to those of Figs. 1 and 2bear the same identifying numerals.

The adjustable feature of the upper mold section with respect to itscarrier may comprise a spider like member that is interposed between thecarrier I2 and the head [3, and that is attached to the carrier atspaced intervals by bolts 80. The interposed member is shown as havingan inner rim 8|, an outer rim 82, and connecting spokes 83. Each spokehas a slot 84 extending lengthwise thereof, and each slot has side wallsand a bottom, the side walls being parallel and the bottom wall beingtapered. A tapered key 85 is slidably movable in each slot, and each keymay be locked in its adjusted position by means of adjusting nuts 86, ona bolt 81 that extends through an opening in an arm 88. Each bolt orstud extends radially from the rim 82, and is rigidly positionedtherein. The spacing spider which may be designated as an entirety bythe numeral 90, may be attached to the head I3 by securing members 9|.

To obtain the desired degree of proximity be-- tween the upper and lowermold sections, as the with minimum effort. the fact that the moldsections may be accurately toggles approach a, straight line position,the

bolts which support the upper head are loosened and the keys are slidalong the slots 84, and

then are locked in place upon the studs 81, whereupon the bolts 80. aretightened as much as possible. The adjustable keys provide a simple andeconomical means for assuring accurate control of the pressure betweenthe meeting faces of the mold section, solely by the operation of themotor.-

An advantage of a press which is made in accordance with my invention isthe fact that the lower mold member, when moved to the lower limit ofits travel occupies a position, which enables an operator to insert orwithdraw an article A further advantage is ing a base, side plates and atop, an upper press head movably suspended from said top, a lower presshead, means. for moving the lower head into engagement with the upperhead so as to support it independently of the top, a diaphragm carriedby the top and forming an expansible chamber therewith, a source offluid supply for the chamber, said diaphragm being adapted to actagainst the upper head and to exert predetermined pressure between itand the lower head while the upper head is supported by the lower head,and means actuated by a, predetermined relative separation of the topand upper press head for releasing the pressure within said chamber uponmovement of the lower head away from the upper head.

2. In a press, a frame, an upper mold member movable upwardly anddownwardly on the frame, a lower mold member, means for moving the lowermember to open and close the press, the lower member, when raised,operating to raise the upper member a short distance, an expansiblefluid-pressure chamber associated with the upper mold member, means forsupplying fluid under pressure to said chamber to exert clampingpressure between the mold members when the press is closed, means forreleasing the pressure in the chamber during the opening of the pressand means actuated by said short upward movement of the upper moldmember for rendering said releasing means inefiective.

3. A press having an upper mold member, a lower mold member, a supportfor the upper member on which the latter member is raisably mounted,mechanism for reciprocating and tilting the lower mold member, meansoperatively connecting said mechanism to the lower mold member forraising it into engagement with the upper member whereby to close themold and lift the upper mold member ofi said support, and means adaptedto act on one of the mold members independently of said mechanism forpressing the mold members together, a device for rendering the lastmentioned means effective and inefiective, said device being actuated bythe upward movement of the lower member into engagement with the uppermember to render the last mentioned means effective.

4. In a press, the combination of a frame, an upper mold member movablycarried thereby, a lower mold member, means for moving the lower memberwith respect to the upper member to close and open the press, said lowermold member operatively engaging the upper member and moving itrelatively to the frame on the closing of the press, an expansible fluidpressure cham ber disposed above the upper mold member, means forsupplying fluid under pressure to said chamber to exert clampingpressure between the mold members, and means actuated by movement of theupper mold member relative to the frame for releasing the fluid pressurewithin the chamber whenever the press is opened.

5. In a press the combination of a frame, a pair of mold members and apair of toggles connected to the frame and to one of the mold membersfor moving it with respect to the other member, said toggles each havingan intermediate pivot thereon, an electric motor supported by the frame,a screw and nut couple operatively connecting the motor to theintermediate pivot of one of the toggles, guiding means connecting theintermediate pivots of the toggles and including a member having a camslot therein receiving an intermediate pivot of one of the toggles, andadditional guiding means for the movable mold member, said guiding meansincluding a cam slot on the frame, and a roller carried by the moldmember and movable in said slot.

6. In a press of the type having an upper and a lower mold member, meansincluding a frame for guiding and moving one of the members aconsiderable distance relative to the other member to open and close thepress, means for guiding the other mold member for reciprocatingmovement, there being an expansible fluid chamber disposed adjacent thelast-mentioned mold member and adapted to effect an independent movementof the same in a direction toward the other mold member when the pressis closed, controlling means for operating fluid in the chamber, saidlast named means comprising a conduit communicating with the chamber anda releasing valve for allowing escape of pressure fluid from thechamber, said releasing valve being actuated in an opening directionconsequent upon a predetermined independent movement of the mold memberaforesaid, whereby when the press is opened, the pressurefluid isreleased from the chamber.

7. In a press, the combination of a frame, upper and lower membersmovably mounted on the frame, means operatively connecting the lowermold member to the frame for moving the latter member toward and awayfrom the upper member to close and open the press, an expansible fluidpressure chamber disposed above the upper mold member, means forsupplying fluid under pressure to said chamber to exert clampingpressure between the mold members after they are brought together, andmeans actuated by movement of the upper mold member on the frame in adirection toward the lower mold member for releasing said fluid underpressure within the chamber.

8. In a press, the combination of a frame, an upper press head carriedby the frame, and a lower press head movable with respect to the upperhead, a pair of toggle members pivotally connected to the lower head andto the frame respectively, and each having an intermediate pivot, ascrew shaft pivotally connected to one of the intermediate pivots, amotor pivotally supported on the frame, gearing operatively connectingthe motor to the screw shaft, a system of linkage including a memberconnected to the intermediate pivot of one toggle and having a cam slotcoacting with the intermediate pivot of the other toggle for connectingthe interme diate pivots together so as to cause movement of them intimed relationship to the movement of the lower head, and guiding meansfor the lower head, said means including a cam slot in the frame and amember connected to the lower head and coacting with the cam slot in theframe to impart a tiltingmovement of the head during the opening andclosin operation of the press.

HENRY C. BOSTWICK.

